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We often rely on a number of different metrics to help create insights into our true project progress. These can range from discrete indicators, such as schedule performance index, to more subjective measures, such as forecasting completion dates based on prior experience on similar projects.

I am asked on regular basis which project progress metrics is my favorite. In other words: If I were marooned on an island with a project status report with only one project metric, which one would I pick?

After careful consideration (and I hope I have more supplies than just a status report when marooned on an island!), I would likely select the estimate to complete (ETC) metric. Here's why:

1. Task ETC tells me much more. Primarily, ETC serves as a simple measure of remaining effort for a task. However, ETC at the task level can shed light on other areas that provide visibility to project progress. To arrive at a task-level ETC, a project team member must take into consideration not only the remaining effort, but other factors such as resource capabilities, resource availability, dependencies and lead times for any task reviews. The rigor required to arrive at a task-level ETC compels team members to think through many variables that influence remaining effort. As you can see, this exercise tells us a lot more than just a number.

2. ETC reduction closely measures true progress. We like to see task-level ETC going down each week at roughly the same pace of the resource capacity we have working on the task. However, ETC figures might not always be reduced at this expected rate. This situation can arise from a number of factors, all which require further inquiry by the project manager. They can include resources assigned to the task being distracted by other projects, delays on deliverables caused by other teams or a potential increase in the remaining forecasted work.

3. ETC can help find major project issues. There are situations when a project team member cannot arrive at a revised ETC figure. When that occurs, it is a strong indicator that visibility to the necessary inputs required to complete the tasks is not present. This should compel you to escalate the lack of visibility as a project issue and pursue remedies. These could include actions such as seeking guidance from subject matter experts, reassigning the task to a more capable team member and increasing interactions with other project teams for their input.

4. Project ETC does what ETC does best. The movement of task-level ETCs can be aggregated to arrive at an overall project ETC. As with task-level ETCs often not being reduced at a desired rate, comparing prior and current ETCs at the project level can point to larger project issues. In addition, the project ETC actually helps you assess the team's ability to achieve the scheduled completion date. You can compare the project ETC against the future resource availability to see if there is sufficient capacity to achieve the desired completion date.

While I like to have a healthy mix of metrics to help gauge project progress, quite often I fall back on ETC as an effective and efficient means of determining project progress as well as the factors that impact this progress.

What is your favorite metric? What are other ways to employ ETC in a project?